The present invention relates to a fuel assembly for a nuclear reactor of light-water type, comprising a plurality of vertical fuel rods which are arranged in spaced relationship between a bottom tie plate and a top tie plate, the bottom tie plate being provided with through-going, vertical channels for conducting water through the bottom tie plate and into the spaces between the fuel rods.
Experience shows that, for example in connection with repairs and service of a nuclear reactor, debris may enter and then move with the water which circulates through the reactor core. The debris may, inter alia, consist of metal shavings (borings) formed in connection with the repair of, for example, a steam separator, pieces of metal wire, or other foreign particles which have entered the system from the outside. The debris may give rise to abrasion damage may have serious consequences if it occurs on parts which are particularly easily damaged, such as fuel rods.
To avoid damage of the above-mentioned kind in pressurized-water reactors, it is known to form the bottom tie plates, already existing under the fuel rod bundles, with a large number of straight vertical holes in order for each bottom tie plate, besides its normal function, to function as a debris catcher in the form of a strainer and prevent debris from reaching the fuel rod bundle with control rod guide tubes and spacers.